胃的超級防護罩：消化大作戰！
The Stomach's Super Shield: Digestion's Grand Battle!
放學後，小惠跑來找小欣老師。「老師，我一直有個問題想不通，」她眨著大大的眼睛問，「我們的胃會消化食物，那它為什麼不會把自己也消化掉呢？」
After school, Leona came to find Teacher Star. "Teacher, there's something I've been wondering about," she asked, blinking her big eyes. "Our stomach digests food, so why doesn't it digest itself?"
小欣老師笑了：「這是個很棒的問題！我們的胃每天都會分泌一種叫做『胃液』的消化液，它非常強大，裡面有鹽酸和胃蛋白酶兩種超級厲害的角色。」
Teacher Star smiled, "That's a great question! Every day, our stomach secretes a digestive fluid called 'gastric juice,' which is incredibly powerful. It contains two superstar components: hydrochloric acid and pepsin."
「鹽酸酸性超強，可以殺死細菌，還能讓食物變性；胃蛋白酶則像一把剪刀，專門分解蛋白質，把大塊的肉類『剪』成小塊。這兩種物質合在一起，連金屬都可能會被腐蝕呢！」小欣老師解釋道。
"Hydrochloric acid is extremely acidic; it can kill bacteria and denature food. Pepsin acts like a pair of scissors, specialized in breaking down proteins, 'cutting' large pieces of meat into smaller ones. Together, these two substances are so powerful they can even corrode metal!" Teacher Star explained.
小惠聽得目瞪口呆：「哇，真的有那麼厲害！那我們的胃怎麼辦？它不會受傷嗎？」小欣老師點點頭：「別擔心，胃有它自己的『超級防護罩』。在胃的內壁上，有一層厚厚的黏液。」
Leona listened, wide-eyed. "Wow, it's really that powerful! So what about our stomach? Doesn't it get hurt?" Teacher Star nodded. "Don't worry, the stomach has its own 'super shield.' On the inner wall of the stomach, there's a thick layer of mucus."
「這層黏液就像一件防酸又防水的雨衣，能把胃液和胃壁隔開，保護胃壁不被強酸和酵素直接傷害。有了它，胃液再強大也碰不到胃壁本體！」小欣老師解釋道。
"This layer of mucus acts like an acid-proof and waterproof raincoat, separating the gastric juice from the stomach wall, protecting the wall from direct harm by strong acid and enzymes. With it, no matter how powerful the gastric juice is, it can't touch the stomach wall itself!" Teacher Star explained.
「原來胃穿著隱形的雨衣啊！」小惠驚呼。「那胃蛋白酶呢？它不會在分泌出來的時候就開始亂剪一通嗎？」小欣老師豎起一根手指：「你問到重點了！胃蛋白酶其實一開始是『不活化狀態』，叫做胃蛋白酶原。」
"So the stomach wears an invisible raincoat!" Leona exclaimed. "What about pepsin then? Doesn't it just start cutting everything as soon as it's secreted?" Teacher Star held up a finger. "You hit on a key point! Pepsin is actually in an 'inactive state' at first, called pepsinogen."
「胃蛋白酶原就像一個被『包裝』起來的酵素，只有當它遇到胃裡的鹽酸，才會被『啟動』，變成真正有活性的胃蛋白酶，開始分解蛋白質。這樣就能確保它只在正確的地方發揮作用！」小欣老師解釋道。
"Pepsinogen is like an enzyme that's 'packaged up.' Only when it encounters hydrochloric acid in the stomach does it get 'activated' and transform into active pepsin, ready to break down proteins. This ensures it only works in the right place!" Teacher Star explained.
「哇，身體真是太聰明了！」小惠感嘆。「那如果這個防護罩不小心壞掉了怎麼辦？」小欣老師臉色變得有點嚴肅：「如果黏液被破壞，讓胃液直接接觸胃壁，就可能造成『胃潰瘍』，會讓胃黏膜受傷甚至出血，很不舒服。」
"Wow, the body is so clever!" Leona exclaimed. "But what if this protective shield accidentally breaks down?" Teacher Star's expression turned a bit serious. "If the mucus layer is damaged, allowing gastric juice to directly contact the stomach wall, it can lead to a 'gastric ulcer,' which can injure or even cause bleeding in the stomach lining, leading to a lot of discomfort."
「造成胃潰瘍的原因有很多，像是長期吃止痛藥、感染幽門螺旋桿菌，或是壓力太大、飲食不正常都會影響胃的防護能力。」小欣老師補充道。
"There are many reasons for gastric ulcers, such as long-term use of painkillers, Helicobacter pylori infection, or excessive stress and irregular diet, all of which can affect the stomach's protective capabilities," Teacher Star added.
小惠點點頭：「原來如此！身體的設計真是太巧妙了，每個環節都配合得剛剛好，才能保護我們。」小欣老師溫和地說：「沒錯，胃的自我保護系統是經過精密協同設計的。下次吃飯時，想想這層默默守護的黏液雨衣，和那些『延後啟動』的酵素包裝，是不是覺得我們的身體很神奇呢？」
Leona nodded, "I see! The body's design is truly ingenious, with every part coordinating perfectly to protect us." Teacher Star said gently, "Exactly, the stomach's self-protection system is a precisely coordinated design. Next time you eat, think of this silently guarding mucus raincoat, and those 'delayed activation' enzyme packages. Doesn't it make you feel our body is amazing?"